Differential phase contrast imaging, also referred to as DPCI, is becoming a promising X-ray imaging modality, for example for mammography. In order to be able to use conventional X-ray tubes providing incoherent X-ray radiation, an absorption grating to produce partly coherent X-ray light waves is provided in relation with the X-ray source, which is why the term “source grating” is used, or G0. Further, a phase grating, or G1, is provided to generate a phase shift between adjacent beams and a further absorption grating G2, also referred to as analyser grating, that is provided to analyse the phase information resulting from the investigated object. Such an arrangement is described, for example, in EP 1 731 099 A1. It has been shown that the grating arrangement has to be adjusted quite accurately in orders of nanometers. However, it has been shown that misalignment occurs, in particular in larger structures, leading to disadvantages in the receivable results.